The focus will be on the need for a theory of memory as a unifying motif in cognitive psychology. There will be dual emphasis on a deeper understanding of coding processes and hierarchical organization of units and on the role of memory in various types of human activity, especially choice behavior. Experimental research will be complemented by mathematical and computer studies of the implications of theoretical concepts. Research goals for the coming year are as follows: Visual processing studies: Although we have made progress toward separating perceptual and decision factors in the identification and recognition of letters, it appears that remaining points of ambiguity may be further resolved by replicating some of the studies of the past year with variations which will permit the use of signal detectability analyses to separate effects of response bias or cognitive strategies from effects of context on perceptibility of letters or letter groups. Also we are shifting our emphasis somewhat toward higher units, attempting to deal more effectively with the problem of the syllable as a unit. Organization in memory: Our immediate objective is to apply and extend the hierarchical association model in some additional contexts. In particular, it appears that the whole problem of chunking as a means of increasing memory capacity amy operate in a somewhat different way in short term and long term memory. Experiments now in the exploratory stage will check out the implications of our theoretical analysis for this problem. Memory for frequency: Two directions appear particularly fruitful. The first is to investigate the problem of the tradeoff between frequency and recency in memory; the second to study judgments of frequency and probability.